Although some species that accumulate only cyanidin (Cy) in nature can produce blue flowers through iron ions, there has been no evidence of blue chrysanthemums being generated in this manner. This study revealed that flavonoid extracts from the ray florets of the chrysanthemum cultivar ‘Wandai Fengguang’ turned blue when exposed to Fe³⁺. Samples that could turn blue were labeled as CB (Cy-determined blue flowers), while samples that did not turn blue were labeled as CN (Cy-determined non-blue flowers). After a series of experiments, a stable screening system was established using flavonoid extracts containing NaAc buffer at pH 5.5 and a total anthocyanin concentration (TAC) of 30 μmol · L^-1, and the addition of Fe³⁺ from 0 to 0.25 μmol · L^-1 allowed for the selection of five CB samples from 39 chrysanthemum cultivars. All five CB samples exhibited flower color phenotypes that belonged to Cluster-Ⅰ with redness (a*) values ranging from 29.03 to 45.99, yellowness (b*) values from −11.31 to 3.77, and brightness (L*) values from 29.07 to 45.99. Additionally, the ratio of TAC to total luteolin content (TLC) was found to be a critical factor for distinguishing between CB and CN samples. To realize the desired blue hue in the flavonoid extracts with the participation of Fe³⁺, a TAC to TLC ratio of 2.25 and above is required. Moreover, the protoplasts and ray florets of CB samples that turned blue with the involvement of Fe²⁺ showed great potential for cultivating blue chrysanthemums through ferric–anthocyanin chelate. Overall, this study reveals that blue flowers can be cultivated through the increase in the iron ion content, combined with the accumulation of Cy.

虽然自然界中一些仅积累花青素（Cy）的物种可以通过铁离子产生蓝色花朵，但目前还没有证据表明蓝色菊花是通过这种方式产生的。这项研究表明，菊花品种“万代风光”的舌状花中的类黄酮提取物在暴露于 Fe ³⁺时会变成蓝色。可以变蓝的样品标记为CB（Cy确定的蓝色花），而不变蓝的样品标记为CN（Cy确定的非蓝色花）。经过一系列实验，以含NaAc缓冲液、pH 5.5、总花色苷浓度(TAC)为30 μmol·L ^-1的黄酮类提取物，并添加0~0.25 μmol· Fe ³⁺ ，建立了稳定的筛选体系。 L ^-1允许从 39 个菊花品种中选择 5 个 CB 样品。所有五个 CB 样品均表现出属于 Cluster-Ⅰ 的花色表型，红度 ( a * ) 值范围为 29.03 至 45.99，黄度 ( b * ) 值范围为 -11.31 至 3.77，亮度 ( L * ) 值范围为 29.07 至 45.99 。此外，TAC 与总木犀草素含量 (TLC) 的比率被发现是区分 CB 和 CN 样品的关键因素。^{为了在 Fe 3+}的参与下在类黄酮提取物中实现所需的蓝色调，需要 2.25 及以上的 TAC 与 TLC 比率。此外，CB样品的原生质体和舌状花在Fe ²⁺的参与下变成蓝色，显示出通过铁花青素螯合物培育蓝色菊花的巨大潜力。总的来说，这项研究表明，通过增加铁离子含量，结合Cy的积累，可以培育蓝色花朵。